Nail feed mechanism



May 3, 1966 Filed Dec. 24, 1964 P. D. CABOT ETAL 3,249,280

NAIL FEED MECHANISM 2 Sheets-Sheet l 2&4

/ Z'IIIA 1 2 Sheets-Sheet 2 P. D. CABOT ETAL NAIL FEED MECHAN SM FiledDec. 24, 1964 May 3, 1966 United States Patent 3,249,280 NAIL FEEDMECHANISM Philip D. Cabot and Robert D. Lowry, Winchester, Mass.,assignors to Lowry Development Corporation,

Winchester, Mass., a corporation of Massachusetts Filed Dec. 24, 1964,Ser. No. 421,022 12 Claims. (Cl. 227-116) This invention relates to anail feeder, and more particularly, to an automatic nail feeder forcontrolledly passing headed nails in single file succession through apassageway leading to a point of desired use, for exampie, to a positionfor successive automatic injection into the barrel of a power naildriving tool.

Nails can be supplied to the entrance end of the feed passageway one byone, either manually or automatically by gravity or otherwise, from amagazine capable of inserting nails one by one sideways head-to-the-rearinto the entrance end of the passageway.

The feeder can be so constructed as to constitute an attachment for anail driving tool and for actuation by motions which are concomitant tonormal operation of the tool. a

A particular object of the invention is to provide an elongated nailfeed passageway into the entrance end of which headed nails may be moreconveniently fed with more accessibility than at a point adjacent itsexit end. Thus, for example, in a preferred embodiment of the'invention, a nail magazine of substantial capacity and hence,bulkiness, instead of being attached to the working end of a tool whereit reduces the utility of the tool in narrow working spaces, is attachedat a point remote from the working end of the tool, but connectedthereto by the intervening feed mechanism of this invention.

A further object of the invention is to provide a nail feed attachmentfor power impact hammers which operates automatically to feed nails oneby one to the working end of the tool as they are needed from a nailmagazine positioned remote from the working end and concomitant to thenormal motions of the tool in use and without requiring independentactuation.

A further object of the invention is to provide a nail feed mechanismwhich, though having moving parts and of considerable length, will be ofan antijamming construction to insure that under no conditions ofoperation can one nail overtake a preceding nail along the feedpassageway.

FIG. 1 is an elevational view of a nail feeding mechanism of theinvention assembled with a'nail driving tool;

FIG. 2 is a detailed cross-sectional view. taken along the line 2--2 ofFIG. 1;

FIG. 3 is a detailed cross-sectional view taken along the line 33 ofFIG. 1;

FIG. 4 is a detailed cross-sectional view taken along the line 44 ofFIG. 1;

FIG. 5 is a detailed cross-sectional view taken along I the line 55 ofFIG. 1;

FIG. 6 is. a detailed cross-sectional view taken along the line 66 ofFIG. 1;

FIG. 7 is an elevational view, partly in cross-section, and broken awayat the top, showing the tool of FIG. 1 with parts thereof in a retractedposition;

FIG. 8 is a view similar to that of FIG. 7 showing the parts in fullytelescoped position;

FIG. 9 is an enlarged fragmentary cross-sectional view showing a nail inthe feeding passageway and indicating, by dotted line position, thefeeding motion thereof;

FIG. 10 is a cross-sectional view taken along the line of 10-10 of FIG.9; and

FIG. 11 is a graphical representation of certain relative dimensions ofthe feed mechanism parts.

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The nail driving tool of FIG. 1 has a lower barrel 12 having a bore 14in which reciprocates an impact rod 16 driven by any suitable mechanismhoused in the main casing 18. The casing 18 is telescopically mountedwith respect to barrel 12 so that, as a nail is driven by the impact rod16, the casing descends with respect to the barrel 12 into a collapsedposition, as shown in FIGS. 1 and 8, but may thereafter be lifted into aretracted position by handle 20 so as to lift the rod 16 in the bore 14to permit a further nail to be loaded into bore 14 below the end of rod16, as shown in FIG. 7. customarily, a spring tends to keep casing 18and barrel 12 separated. In driving a nail, hand pressure on handle 20compresses the spring.

In the tool shown, barrel 12 has adjacent its bottom end a longitudinalslot 22, through which a nail may be loaded into bore 14 while the rod16 is in retracted position. A hollow nail feed housing 24 partiallyoverlaps longitudinal slot 22 and extends up the same side of the barrel12 above the slot 22, being clamped over and bolted to ribs 26 extendingoutwardly from the side of barrel 12 in alignment with slot 22.

A bar 30 having a series of inwardly facing notches forming a successionof downwardly facing abutments 31, 32 and 33 is hung inside housing 24on a pin 34 (FIG. 10) which protrudes through a pair of opposed slots 36in the housing side walls. The top of the bar is bevelled at 37 and thebar is urged inwardly by a series of three spaced compression springs 38for yielding compound rocking movement within the housing.

An opposed inner slide bar 40 is fastened at its upper end to the toolcasing 18 by being hooked under a strap 39 and protrudes down intohousing 24 inside bar 30, and with its inside surface bearing at the topagainst a bevelled filler piece 40a fast on casing 18 and, lower down,against outer bevelled faces of the series of ribs 26. The bar 40 alsohas a series of notches which, taken with its forward end 41, form aseries of downwardly facing abutments 41, 42, 43 and 44.

Slide bar 40 lies in the path of movement of a protrusion 46 on the toolcasing 18 'so that, as the tool casing begins its downward motion, theprotrusion 46 first comes into engagement with the upper end of bar 40and then moves it down into the position shown in FIG. 8 relative to theopposed bar 30.

The casing 18, with its attached slide bar 40, and the barrel 12, withits attached bar 30, thus constitute a pair of relatively slidablemembers forming between the two bars 30 and 40 a laterally expansiblepassageway 47 for accommodation and movement of nails down the side ofbarrel 12 after they are inserted into the top entrance of passageway 47below the rear abutment 44 of the slide bar 40, one at a time at eachfull retraction of the tool casing.

While the nails may be manually fed into the top of the passageway 47, aslotted magazine or clip 48 of known construction which has spacednail-head supporting shoulders 49 forming a chute 50 and includes aspring pusher 51 urge a single row of nails sideways towards and intoengagement with the slide bar 40. The chute walls extend inwardlybetween side wall extensions 52 of housing 24.

The inside contour of the bottom of housing 24 is such as to contain aswing latch 54 constantly urged into barrel slot 22 by a spring 55. Thislatch 54 is swung back as a nail is pushed downwardly by the end 41 ofinner slide bar 40 to bring its head into engagement with spacedshoulders 56, its head then clearing the bottom of lowest rib 26,whereupon the latch pushes the nail through slot 22 unless impeded bythe presence of a previously positioned nail or rod 16.

The antijamming feature of the invention resides in i the relativespacings of the abutments 31, 32 and 33 with respect to the spacings ofthe abutments 41, 42, 43 and 44. These spacings are graphically shown inFIG. 11 wherein the distance between 31 and 32 on bar 30 exceeds, by anincrement of B, the distance A between abutments 41 and 42 on slide bar40; the distance between abutments 42 and 43 on slide bar 40 exceeds A,by 2B; that between 32 and 33 exceeds A, by SE; that between 43 and 44exceeds A, by 4B; and that between 33 and the top of the most advancednail (indicated in FIG. 11 as 54) in chute t exceeds A, by SE; A and Bbeing constant throughout. In this way, as slide bar 40 is retracted,its bottom end abutment 41 will necessarily pass by abutment 31, beforeabutment 42 passes abutment 32; abutment 43 will not pass abutment 33until after abutment 42 has passed abutment 32 and so on.

Accordingly, one is assured that if there is only a partial retractionof the inner bar 40, it can never pick up a succeeding nail in the lineof succession in passageway 47 for advancing downward movement until ithas already picked up every preceding nail in the line of succession.Overlapping and, hence, jamming of the nails in the passageway is thusprecluded.

Similarly, one is assured that on an advancing stroke from full bar 4iretraction, starting with 44 (FIG. 11) above 54, abutment 43 cannotdeliver a nail to abutment 32 before 42 has delivered any preceding nailto 31; and 44 cannot deliver a nail to 33 until 43 has delivered anypreceding nail to 32. Thu-s, if there is a full forward stroke, eachnail will be advanced a full step to in front of the next bar 30abutment, timewise, in their order of succession. Hence, if there isonly a partial forward stroke of bar 40, no succeeding nail in thesuccession of nails in the passageway will ever be delivered a full stepto a next bar 30 abutment before all preceding nails in the passagewayhave positively been delivered their full step to the next bar 30abutment.

In addition, then, to preventing jamming of the nails in the passagewaybecause of only a partial retractive stroke, jamming of the nails in thepassageway will also be precluded despite an interrupted forward stroke.In short, no matter how far, or in what direction, the barrel and casingof the tool are telescopically moved relative to one another, and nailsin the passageway 47 will remain in a separated order of successsion anda proper feed of a single nail to bore 14 can be reliably accomplishedwhenever bore 14 is empty merely by fully retracting the casing and thenadvancing it through one or more full strokes until the first nail inthe line of succession is delivered to the bore.

-It will be understood that the resilient action of the outer bar 30holds each nail frictionally against the opposing surface of slide bar40 so that no nail will move downwardly except when propelled by a bar40 abutment and can never be moved by frictional engagement with bar 40upwardly past any abutment on bar 30 which it has previously passed downbeyond.

It will be further understood that a greater or less number of abutmentsmay be provided on the bars 30 and 40 depending upon the length of thestroke of casing 18 relative to barrel 12 and the penny size of thenails being fed. In any event, the stroke of bar 40 should be such thatall but its lowermost and uppermost abutments will pass by two opposingbar 30 abutments in each full stroke so that they (or it) pick up anynails lodged against upper bar 30 abutments and propel their heads to ora little beyond the next lower bar 30 abutment, by which they each willbe engaged as the slide bar is retracted. Thus in FIG. 9, the head ofthe nail shown has, during a retraction stroke of slide bar 40, lodgedagainst abutment 32. As bar 40 moves down on the next stroke, abutment42 will engage the nail head from the opposite side and move itdownwardly with respect to bar 30 to the dotted line position andultimately advance the head beyond the next lower abutment 31.

The lost motion provided by the attachment of slide bar 40 to casing 18through strap 39 is required in the form of the invention shown in thedrawings so that the total possible stroke of impact rod 16 with respectto barrel 12, shown by the scale line in FIG. 8, will be greater thanthe stroke of slide bar 40. Otherwise, impact rod 16 might either notclear slot 22 on the upward stroke of casing 18 or not countersink thenail by moving beyond the end of barrel 12 when the casing is fullycollapsed down onto barrel 12.v

In practice, the stroke of slide bar 40 for the device shown in thedrawings must be at least A and SE to insure that abutment 44: passesabutment 33 on the downward stroke. The total stroke ofimpact rod thenis at least A and 5B and C, where C represents the space, at fullretraction of casing 18, between protrusion 46 and the top of bar 40.

A handle 60 may be superimposed over the magazine 48 and made fast tohousing extensions 52. In such case, the handle 20 though shown in thedrawings as being in the plane of handle 60 can better be radiallyoff-set from handle 60, for example by so that the handles may morereadily be grasped in separate hands for separating motion to cock thenail feed mechanism.

It will also be understood that impact rod, by virtue of electricallydriven cam or other reciprocating mechanism housed in casing 18 andconstituting no part of this invention, has a rapid short repetitivenail driving stroke with respect to casing 18 entirely independent ofthe relative telescoping motion of casing 18 relative tov barrel 12.

What is claimed is:

1. A nail feed mechanism comprising a pair of opposed relativelyslidable members forming therebetween an intervening confined passagewayfor single-file passage of headed nails;

a series of forwardly facing spaced abutments on each of said membersfor engaging, from opposite sides of said passageway, the rear surfacesof heads of nails passing point-first along said passageway;

one of said members being slidably movable relative to the other memberfrom a fully retracted position whereat successive abutments on said onemember are retracted behind successive abutments on said other member toa fully advanced position whereat each of the abutments other than thefirst and the last in the series of abutments on said one member hasmoved past two adjacent abutments on said other member to advance asingle file progression of nails, inserted in succession into saidpassageway in front of said last abutment on said one member,step-bystep from abutment to abutment of said other member along saidpassageway with each full stroke of said one member.

2. A nail feed mechanism as claimed in claim 1 wherein the series ofabutments on said other member are mounted for resilient movementtowards and away from said one member to provide a yieldingly expansiblepassageway therebetween for yieldingly accommodating theheads of nailspassing therethrough.

3. A nail feed mechanism as claimed in claim 2 wherein the resilientlymounted series of abutments are mounted for rocking movement withrespect to the axis of said passageway.

4. A nail mechanism as claimed in claim 1 which includes a longitudinalslot in the side of said other member adjacent the rear end of saidpassageway for insertion of nails sideways into said passageway in frontof said last abutment of said one member in its fully retractedposition.

5. A- nail feed mechanism as claimed in claim 1 which includes alongitudinal slot in the side of said other member adjacent the rear endof said passageway for-insertion of nails sideways into said passagewayin front of the rear abutment on said one member in its fully retractedposition and a longitudinal slot in the other side of said other memberadjacent the exit end of said passageway for passage of nails one at atime sideways out of such passageway from in front of the forwardabutment of said one member in its fully advanced position.

6. A nail feed mechanism as claimed in claim 5 wherein said other memberincludes a barrel of a nail driving tool and the nail exit end of saidpassageway communicates with a longitudinal slot in said barrel throughwhich nails emerging from the exit end of said passageway may passsideways into said barrel into a position to be driven by saidnail-driving tool.

7. A nail feed mechanism as claimed in claim 6 wherein said one memberincludes a nail-driving tool casing which reciprocates with respect tosaid barrel and moves towards said barrel as a nail is driven out ofsaid barrel by said nail-driving tool.

8. A nail feed mechanism as claimed in claim 1 where the distancebetween said abutments of at least one of said members progressivelyincreases from the nail exit to the nail entrance end of saidpassageway.

9. A nail feed mechanism as claimed in claim 1 wherein said memberscomprise, respectively, a casing for the nail driving mechanism of anail-driving tool having a reciprocating impact rod and a barreltelescopically mounted on said casing providing a bore within which saidrod reciprocates, and said passageway extends from a point remote fromthe end of said barrel to a point adjacent the end of said barrel,offset from said bore.

10. A nail feed mechanism as claimed in claim 9 wherein said series ofabutments on said casing have lost motion with respect to thetelescoping motion of said casing relative to said barrel, whereby thestroke of said telescoping motion is greater than the stroke of saidcasing series of abutments.

11. A nail feed mechanism as claimed in claim 1 wherein the distancebetween the abutments on both of said members progressively increases bya uniform increment from the nail exit to the nail entrance end of saidpassageway.

12. A nail feed mechanism as claimed in claim 11 wherein the distancebetween the first two abutments on said one member nearest the nail exitend of said passageway is less than the distance between the first twoabutments on the other member nearest the nail exit end of saidpassageway and during retraction of said one member, its series ofabutments moves past the opposite series of abutments progressively fromfront to rear of said passageway, whereby the head of a nail in saidpassageway lodged against a succeeding abutment in said opposite serieswill not be passed on a retractive stroke by a succeeding abutment onsaid one member before the head of every nail in said passageway lodgedagainst a preceding abutment in said opposite series has been passed bya preceding retracting abutment.

No references cited.

GRANVILLE Y. CUSTER, JR., Primary Examiner.

1. A NAIL FEED MECHANISM COMPRISING A PAIR OF OPPOSED RELATIVELYSLIDABLE MEMBERS FORMING THEREBETWEEN AN INTERVENING CONFINED PASSAGEWAYFOR SINGLE-FILE PASSAGE OF HEADED NAILS; A SERIES OF FORWARDLY FACINGSPACED ABUTMENTS ON EACH OF SAID MEMBERS FOR ENGAGING FROM OPPOSITESIDES OF SAID PASSAGWAY, THE REAR SURFACES OF HEADS OF NAILS PASSINGPOINT-FIRST ALONG SAID PASSAGEWAY; ONE OF SAID MEMBERS BEING SLIDABLYMOVABLE RELATIVE TO THE OTHER MEMBER FROM A FULLY RETRACTED POSITIONWHEREAT SUCCESSIVE ABUTMENTS ON SAID ONE MEMBER ARE RETRACTED BEHINDSUCCESSIVE ABUTMENTS ON SAID OTHER MEMBER TO A FULLY ADVANCED POSITIONWHEREAT EACH OF THE ABUTMENTS OTHER THAN THE FIRST AND THE LAST IN THESERIES OF ABUTMENTS ON SAID ONE MEMBER HAS MOVED PAST TWO ADJACENTABUTMENTS ON SAID OTHER MEMBER TO ADVANCE A SINGLE FILE PROGRESSION OFNAILS, INSERTED IN SUCCESSION INTO PASSAGEWAY IN FRONT OF SAID LASTABUTMENT ON SAID ONE MEMBER, STEP-BYSTEP FROM ABUTMENT TO ABUTMENT OFSAID OTHER MEMBER ALONG SAID PASSAGEWAY WITH EACH FULL STROKE OF SAIDONE MEMBER.